Method and apparatus for non-surgical treatment of carpal tunnel syndrome

ABSTRACT

An apparatus and method of use for treating carpal tunnel syndrome designed to permit delivery of a sustained release, depot form of a corticosteroid agent at an adequate therapeutic dosage, directly into the center of the carpal tunnel. The apparatus consists of an armboard adapted for receiving and securing a human forearm and hand. In a preferred embodiment, the armboard also includes at least one forearm bracket and at least one wrist bracket having an integrally formed centering pointer and needle guide for delivery of medication into the carpal tunnel. In one embodiment of the method of use, an anesthetic agent and a corticosteroid are delivered by a needle installation directly into the anatomic center of the carpal tunnel in order to produce the desired pharmacological effects.

This is a division of application Ser. No. 08/083,748 filed Jun. 28,1993, now U.S. Pat. No. 5,425,707.

This invention pertains generally to a method of treatment for carpaltunnel syndrome and, more specifically, to a non-surgical method andapparatus for such treatment the use of which permits therapeutic agentsto be delivered directly into the carpal tunnel.

BACKGROUND OF THE INVENTION

Carpal tunnel syndrome is among the most frequently encounteredneuro-musculoskeletal disorders. Initially described by Sir James Pagetin 1853, the syndrome of median nerve entrapment has been recognizedtraditionally as primarily a disease of middle life. Recently however,its incidence and prevalence have been increasing among both youngerpersons and those beyond middle life.

The increase in occurrence of carpal tunnel syndrome has been coincidentwith a number of factors including lengthening life expectancy. However,a particularly significant factor appears to be the ubiquity of thecomputer keyboard in both the home and the office. Indeed, because ofthe wide spread use of the computer in the home and in clerical andoffice employment, the incidence of carpal tunnel syndrome has increaseddramatically. Moreover, it is estimated that afflicted females outnumber males at a ratio of from 3:1 to 5:1.

The carpal tunnel is a semi-nondistensible, open-ended and approximatelycylindrical anatomical compartment bounded by the carpal bones and theflexor retinaculum, a.k.a. the flexor carpal ligament. The carpal tunnelis situated beneath the soft tissues at and just proximal to the wrist,with its long axis parallel with the axial plane of the arm. The carpaltunnel is traversed by the flexor tendons of the hand, the vascularsupply of the median nerve and the median nerve itself. The median nervesupplies sensory and motor functional innervations to a substantial andrather distinct portion of the human hand. In the transverse plain, atthe level of the distal forearm, the median nerve lies immediatelybeneath the flexor retinaculum; the flexor tendons to the hand lie deepto the median nerve.

The median nerve is the softest structure within the carpal tunnel, andwhen intraluminal pressure becomes augmented or increased, the vectorsof force are exerted upon and against the median nerve and its bloodsupply. Patients with carpal tunnel syndrome suffer from elevatedintraluminal pressure, such as that resulting from inflammation due to amyriad of potential underlying pathophysiological etiologies, or all toooften, without any apparently identifiable reason. Specifically, whereintraluminal pressure within the carpal tunnel increases, theconsequential impingement of the median nerve and its blood supply leadsto circulatory compromise in the median nerve. This compromise in bloodflow in turn, slows the rate of median neural conduction which ismanifested by an objective functional impairment of the hand. Thisimpairment may be acutely exacerbated by certain mechanical stresses.

The most frequent complaints of carpal tunnel syndrome are hand pain anda numbness characterized by the classic "text book description" ofcarpal tunnel syndrome which includes: burning, nocturnal hand pain,which generally is sufficient to awaken the patient from sleep, andwhich may be temporarily relieved by shaking or suspending the hand andforearm in a dependent position. This pain may also radiate proximallyto the forearm or elbow, and, at times, even as far as the shoulder.Numbness occurs along the distribution of the median nerve, whichincludes the anterior surfaces of the thumb, index finger, middlefinger, and the radial half of the ring finger, as well as the distalpalm. Loss of tactile sensation or thenar muscle atrophy often resultsin patient complaints of clumsiness or incoordination of the affectedhand(s). Muscular wasting is a relatively late phenomenon in thedevelopment of the carpal tunnel syndrome disease process.

Traditionally, treatments employed for carpal tunnel syndrome have beenclassified as either curative or palliative. Of the curative treatments,surgical release and decompression is considered the only viable andtherefore accepted method. One example of a recent development in thesurgical treatment of carpal tunnel syndrome is disclosed in U.S. Pat.No. 5,089,000 to Agee et. al. However, even an intervention so seeminglydefinitive as surgery does not enjoy unequivocal success as propitioustherapy for carpal tunnel syndrome. Although conventional operativerelease and decompression of the carpal tunnel has been deemed the onlycurative modality available, it appears that surgical success, as thatterm is used in authoritative text in professional journals describeoperative results or outcomes which fall short of permanent abatement ofall clinical manifestations of carpal tunnel syndrome. It is estimatedthat as many as approximately 30% of the cases treated via surgery havefailed that modality. In other words, surgical success and operativecure are not synonymous terms in the applicable literature.

Even in those published reports which fail to specifically delineatequalifications for successful surgical treatment, a low threshold forcategorization of a surgical result as successful may be inferred fromthe usual very narrow definition of a surgical failure. Most often acase is considered to have failed surgically where no identifiableimprovement occurs immediately after surgery, or where symptoms recurduring the proximate post,operative convalescent period.

Moreover, because the surgical methods used to treat carpal tunnelsyndrome necessarily give rise to some tissue damage and scarring in orabout the carpal tunnel, the resultant inflammatory response increasesintraluminal pressure post-surgically. This increase in some individualsis permanent, thereby exacerbating this condition in a number ofpatients.

In sum, surgical treatment for carpal tunnel syndrome, althoughpotentially curative in some cases, is probably more often in reality, apailiative technique which is ineffective in a large fraction (up to30%, or more over time) of patients. Clearly, operative management ofcarpal tunnel syndrome has a number of inevitable and potentialdrawbacks all of which are self-evident.

Carpal tunnel syndrome has recently become the second leading cause oftime lost from work due to disability. Employment-related carpal tunnelsyndrome presents a number of heretofore unresolved problems relating toa number of factors. Central among these factors is that no knowntherapeutic modality adequately treats the problem. Specifically, forexample, following surgery for employment-associated carpal tunnelsyndrome, the patient-employee suffers early reoccurrence of his/hersymptoms, even where the work load and duration of work stress have beendramatically reduced. The relevant medical literature has not offeredany substantial explanation or recommendation therefore directly.However, two relatively contemporaneous reports, do explain thesituation. For example, computerized axial tomography (CAT) scans of thecarpal tunnel were obtained before and after surgery for work-relatedcarpal tunnel syndrome. The CAT scans demonstrated that, followingdivision of the flexor retinaculum, the contents of the carpal tunnelsubluxed distally and palmarly. Considering this displacement in lightof the poor results following carpal tunnel syndrome surgery, inwork-related cases, it can reasonably be inferred that such surgery, infact, places the median nerve and other carpal tunnel contents in aposition more vulnerable to the forces causing the malady in the firstplace, yet without the buffering protection of the intactflexor-retinaculum.

Although a number of palliative measures have been advanced asalternatives to surgical intervention, these measures provide verylimited, if any, therapeutic benefits. Palliative therapies include forexample, volar, i.e,, palmar or anterior, splinting, short-arm andtransversing the wrist joint; elevation of the wrist; administration ofnon-steroidal anti-inflammatory drugs, e.g., aspirin, indomethacin andibuprofen and their progeny; diuretic agents which may be prescribedintermittently; and administration of corticosteroid drugs. Any limitedbenefits that palliative therapies can provide are provided only veryearly on in the course of carpal tunnel syndrome or where carpal tunnelsyndrome is present in its mildest form. Thus, the effectiveness ofpalliative therapy is at best, inconsistent, transient or equivocal, andat worst, may be harmful to the patient.

Corticosteroid administration is perhaps the most interventional andcontroversial among the various palliative measures traditionallyemployed in the treatment of carpal tunnel syndrome. Towards this end,investigators and clinicians have administered corticosteroid agentsboth systemically, by mouth or parenterally, and locally, by injection.Regardless of the route or cite of steroid administration employed inthe therapeutic endeavor, authoritative texts which speak to this matterhave generally been uniformly unenthusiastic in describing the efficacyof corticosteroid drugs in the management of carpal tunnel syndrome.

Since the time corticosteroid injection therapy was first employed inthe management of carpal tunnel syndrome over three decades ago,virtually the identical methodology and location of that technique hasbeen repeatedly adopted, without any material change or refinement.Technically, the traditional injection technique as recorded in themedical literature is neither a site specific injection nor a treatmentof carpal tunnel syndrome, but merely a local injection at the wristutilized as a palliative measure in the presence of median nerveentrapment. As shown in photographs and drawings contained withinreported medical literature, the traditional mode of injection depositsmedication approximate to the median nerve at a point near, at, orbeyond the entrapped nerve's exit from the distal canal.

Review of the particular corticosteroid agents and their dosagesemployed in traditional corticosteroid injections for carpal tunnelsyndrome reveals that these drugs are generally short-acting, often ofonly mild-to-moderate potency, or are administered in inadequate doses.Significantly however is that the direction of conventional injectionsis the same as the direction of the flow of the blood and synovialfluid. This not only carries the instillant away from the carpal tunnel,but also, since it is proximate to a rich vascular arcade, this type ofinjection hastens its removal from the site of its local injection intothe systemic circulation. This, in no small way, contributes to thetransient nature of whatever benefits might be conferred.

Finally, traditional corticosteroid injections are performed only by alimited number of medical specialists, most of whom are the samephysicians who perform the carpal tunnel release surgery. A number ofpotential complications of corticosteroid injection have been advanced;the most serious of which are impalement of the median nerve andchemical neuritis.

It can be seen from the foregoing that it is desirable to havenonoperative techniques and instrumentalities for the treatment ofcarpal tunnel syndrome which are substantially more effective to thosemethods of treatment currently used.

It is an object of the present invention to provide techniques anddevices for the treatment of carpal tunnel syndrome which are viablealternatives to surgical treatment methods and eliminate the risk andcomplications associated with carpal tunnel syndrome surgery, inappropriate patients (which includes the majority).

It is also an object of the present invention to provide patients withgreater accessibility to effective therapy for the treatment of carpaltunnel syndrome.

Yet another object of the present invention is to provide a method oftreatment for carpal tunnel syndrome which significantly reduces thecost of healthcare associated with its treatment.

Still another object of the present invention is to provide a treatmentmethod for carpal tunnel syndrome which eliminates the peri-operativepatient pain, inconvenience, and prolonged recuperation associated withtraditional treatment methods.

Another object of the present invention is to provide a treatmentmodality which is effective in cases considered to be prognosticallypoor for or which have failed surgery.

Yet another object of the present invention is to provide an effectivenon-surgical treatment method for carpal tunnel syndrome which may beperformed by a variety of medical specialists.

These and other objects of the present invention are fulfilled by thenovel technique and instrumentality set forth herein.

BRIEF SUMMARY OF THE INVENTION

The novel technique employed in the instant invention entails the use ofan apparatus specifically designed to permit delivery of a sustainedrelease, depot form of a corticosteroid agent at an adequate therapeuticdosage, directly into the center of the carpal tunnel. Thecorticosteroid is delivered by a needle installation directly into theanatomic center of the carpal tunnel in order to produce the desiredpharmacological effects associated with the use of corticosteroids.These pharmacological effects include both the early anti-inflammatoryeffects caused by corticosteroid agents, as well as delayed benefitsderived from inhibition of scar formation and fibrinogenesis which areseen as latter positive pharmacotherapeutic manifestations withsustained corticosteroid activity after injection of one of the newersynthetic, long-acting agents. The apparatus for the novel techniqueherein makes treatment of carpal tunnel syndrome a procedure that can beperformed by virtually by any physician. In addition, among the otheradvantages, the novel technique entails injection at and into a sitewhich is not in proximity to the median nerve itself thereby removingthe risk of impalement and chemical neuritis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of an embodiment of the armboard of theinstant invention.

FIG. 2 is a side cross-sectional view of the apparatus of FIG. 1 at line2a-2b.

FIG. 3 is a top plan view of the apparatus of FIG. 1, shown with arepresentation of a human forearm and hand.

FIG. 4 is a cross-sectional schematic view of the apparatus shown inFIG. 3, taken along the lines 4a-4b.

FIG. 5 is a top plan view of the wrist bracket and central needle guideportion of the apparatus shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, there is shown one embodiment of the limb-restraint,injection support armboard 1, of the present invention. As depicted inthe embodiment shown, armboard 1 is a generally flat, rectangular shapehaving a proximal end 2, a distal end 4, two side ends 6, an upperplanar surface 8, and a lower planar surface 10, separated by wristflexion curb 12. Upper planar surface 8 and lower planar surface 10include an arm support member 14, which is preferably a depression orchannel, and which may be more preferably, a generally "u-shaped"channel. Arm support member 14 may also be preferably located generallycentrally within the body of the armboard. Arm support member 14 isformed so as to receive and generally support the human forearm on upperplanar surface 8, and to receive and generally support the hand on lowerplanar surface 10, of the armboard.

Situated at or near flexion curb 12, preferably on upper planar surface8 are a pair of adjustable side brackets 16, each having side bracketadjustment slots 18 and side bracket set screws 20. Side bracket setscrews 20 permit side brackets 16 to be mounted on armboard 1 andfacilitate the adjustment and securing of a human forearm, preferablyanchoring the forearm and wrist within arm support member 14, at or nearthe ulnar and radial styloid processes. In the embodiment depicted, sidebracket set screws are wing-nuts; however, other similar mated-threadassemblies and other alternative mounting and securing means may be usedincluding, for example, compression fittings, sliding fasteners, orratcheted post and guides.

Preferably, side brackets 16 are located directly opposite each otherand are moveable in an inward-outward direction relative to each other,as well as in planar arcuate directions. Side brackets 16 includeforearm positioning surfaces 22, which may be contoured, cushioned orotherwise molded to firmly secure a forearm in place with minimumdiscomfort to the patient. In other, alternate embodiments of thearmboard of the present invention, one of the side brackets may be fixedin-place with the other being adjustable in the manner described above,so as to allow adjustment of the forearm to occur at one side of theforearm with the opposite side bracket being essentially stationary. Inother embodiments of the armboard of the instant invention, alternativesecuring means for securing the forearm and wrist may be used,including, for example, clamps or straps which may include hook andpile, velcro-type fasteners.

When in use, a patient's forearm and hand is placed in the armboard,palmar side-up and is positioned in arm support member 14 so that thewrist will lie approximately at or near wrist flexion curb 12. Wristflexion curb 12 facilitates proper flexion of a patient's wrist togenerally expose and provide access to the carpal tunnel. Properplacement will put the patient's hand in a range of approximately 10 to30 degrees of dorsi-flexion, with the preferred degree of dorsi-flexionof approximately 20 degrees. Wrist flexion curb 12 may be incorporatedin the armboard as a slope or ramp with the appropriate angularorientation or it may be an angular 90 degree drop-off or ledge of notmore than roughly 3 inches between the upper and lower planar surfaces.Wrist placement may also be further facilitated by the use ofpositioning blocks, wedges or other shapes including those dictated bypatient comfort considerations, which may be placed under the handand/or forearm.

Positioned at or near flexion curb 12 and preferably above the plane ofside brackets 16, is wrist bracket 24. Wrist bracket 24 includes a pairof wrist bracket adjustment slots 26, and may also include centralneedle guide 30 which may be mounted directly to armboard 1, via wristbracket adjustment screws 28. In alternate preferred embodiments, wristbracket 24 may be offset and mounted above side brackets via sidebracket adjustment screws 28. In other alternative embodiments, wristbracket 24 may have only a single adjustment slot for mounting andadjustment. In these embodiments, the wrist bracket remains essentiallyadjustable in the manner described above. Still, in other alternativeembodiments, needle guide 30 may be mounted onto the armboard,separately and apart from wrist bracket 24.

Located generally centrally within wrist bracket 24 is needle guide 30.Guide 30 includes at its proximal side edge centering-pointer 32, needleentrance 34, needle channel 36 (shown in outline detail) and needle exit38. Needle channel 36 lies between needle entrance 34 and needle exit38. Centering pointer 32 also includes viewing aperture 40 for viewingneedle insertion between the two central tendons of a patient's forearm.In one preferred embodiment of the present invention, viewing aperture40 is simply a opening or void in the centering pointer. In otherpreferred embodiments, viewing aperture 40 may include a magnifying lensand/or lighting means to facilitate viewing of a needle injection siteprior to the needle's insertion into a patient's forearm. Needleentrance 34 is preferably constructed so as to permit insertion therethrough a flexible sterile needle and through which a drug deliverycanula, also preferably flexible, may be passed into the needle interiorand ultimately to the carpal tunnel. Upon insertion of the flexiblesterile needle into the needle entrance, through the channel and out ofthe needle exit, a medication delivery tube will typically be insertedtherein with the needle being then withdrawn from the injection site. Apreferred medication dosage formula may then be infused directly intothe injection site. In one preferred embodiment, needle entrance 34 mayalso include at the end opposite the needle channel, needle hub 42 andsyringe adapter 44. Needle hub 42 facilitates attachment of syringeadapter 44 to a cannula or conduit which may be used to infuse aninjection site. Syringe adapter 44 is a multi-way valve, such as athree-way stopcock valve, which permits infusion of medication fromsyringes 46 and 48. In other preferred embodiments, a single needle andsyringe may be used to deliver medication to the carpal tunnel.

Armboard 1, and its major component structural parts are preferably madeof rigid or semi-rigid materials from which the apparatus made be easilyand economically fabricated. Suitable materials for the construction ofthe apparatus or its component parts include, for example, nylon, ABS,or other light-weight durable plastics or may be made of metal,including aluminum, stainless steel or other materials, includingreinforced fiberglass, ceramic composites, or combinations of thesematerials which are capable of withstanding both repeated use andsterilization processes whether by heat or chemicals. Moreover, thevarious component parts, such as side brackets, forearm positioningsurfaces, wrist brackets and needle guides may also be made in differentsizes to accommodate the forearm sizes of a variety of patients, forexample, as between younger and older patients or between male andfemale patients.

Finally, in other preferred embodiments of the armboard of the instantinvention, the forearm bearing surface of armboard 1 may be constructedso to form a pair of opposed inclines or ramps, with the wrist flexioncurb forming the apex of the two inclines. The incline forming the upperplanar surface will support the forearm proper and the incline formingthe lower planar surface will support the hand. In these embodiments,the wrist will be placed at the wrist flexion curb with the forearm andhand resting on the arm support member in the manner described above.

In FIG. 2 is shown a side cross-sectional view of the armboard of FIG. 1at line 2a-2b. The portion of armboard 1 including proximal end 2,generally carries upper planar surface 8, whereas the portion designateddistal end 4, includes lower planar surface 10. Shown in partial outlineis arm support member 14, depicted as a generally "u-shaped" channeldefined at its upper surface edge by upper planar surface 8. Arm supportmember 14 is preferably of sufficient depth to permit a patient'sforearm to rest securely therein. Separating upper and lower planarsurfaces is wrist flexion curb 12, generally shown as a slope having anangle of between 10 to 30 degrees, and preferably, having a slope ofapproximately 20 degrees.

Positioned at or near flexion curb 12, is adjustable side bracket 16. Inthe embodiment shown in FIG. 2, side bracket 16 is moveable in aninward-outward direction relative to the plane of the drawing, as wellas being moveable in an arcuate direction across the drawing plane. Sidebracket 16 includes forearm positioning surface 22, which may becontoured, cushioned or otherwise adapted to firmly secure a forearm inplace, preferably anchoring the forearm at the ulnar and radial styloidportions. Side bracket 16 is adjustable via bracket adjustment slots 18(not shown) and side bracket set screws 20 (shown in phantom detail). Inalternate embodiments, one side bracket may be non-moveable, so as toallow securing and adjustment of the forearm to occur only on one sideof the forearm with the member of the opposite side bracket pair beingadjustable.

Positioned at or near flexion curb 12 and at the terminus of arm supportmember 14 is wrist bracket 24. Wrist bracket 24 includes central needleguide 30. In the embodiment shown, wrist bracket 24 is mounted toarmboard 1, via a pair of wrist bracket adjustment screws 28. Inalternate embodiments, wrist bracket 24 may have only a singleadjustment slot and screw for mounting and adjustment. Guide 30 includesat its proximal side edge centering pointer 32, needle entrance 34,needle channel 36 (shown in phantom detail) and needle exit 38. Needlechannel 36 lies between needle entrance 34 and needle exit 38.

FIG. 3 shows a top plan view of the apparatus of FIG. 1, shown with arepresentation of a human forearm and hand. When the armboard is in use,the forearm and hand may be placed in the centrally located arm supportmember 14, with the elbow portion of the forearm situated at or nearproximal end 2. The forearm and hand are positioned palmar side-up andare advanced towards distal end 4 of armboard 1, until the point oftransition occurring at wrist flexion curb 12. By placing theflexor-palmar crease of the wrist portion of the forearm at wristflexion curb 12, the wrist will be in approximately 20 degrees ofdorsi-flexion, thereby providing access to the carpal tunnel frombetween the two central tendons, designated CT-1 and CT-2. After thewrist is in proper placement at wrist flexion curb 12, side brackets 16are moved inwardly to bring forearm positioning surfaces 22 in contactwith the lateral surfaces of the forearm, preferably at the ulnar andradial styloids. The forearm is then secured in place by side brackets16 via side bracket adjustment screws 18.

After securing the forearm in place, wrist bracket 24, carrying centralneedle guide 30 is brought into position over the forearm. Typically thepatient's forearm may then be prepared for sterile technique as iswell-known in the art. Wrist bracket 24 further secures the forearm atthe palmar surface of the wrist by providing downward force on thatsurface which may be adjusted by wrist adjustment screws 28. As part ofsecurement of the wrist, centering pointer 32 is brought into positionbetween the two central tendons of the forearm. Centering pointer 32includes viewing window 40 for visual inspection of the injection siteon the forearm above the carpal tunnel. After proper placement ofcentering pointer 32 and after wrist bracket 24 is secured in place, aflexible needle is advanced into needle entrance 34, through needlechannel 36 and out of needle exit 38. Preferably, the flexible needleused will be of sufficient length to traverse the entire length of theneedle guide without requiring excessive compression of the forearm bywrist bracket 24 in order to reach the carpal tunnel. Typically, theneedle used will be from 20 to 26 gauge and will be from 1 to 3 inchesin length, preferably 1.5 to 2 inches, depending on the size of thepatient's forearm, the configuration of the wrist bracket assembly andthe placement of the forearm within the forearm channel. It is importanthowever, to bear in mind that the needle need only be of sufficientlength to permit the needle tip to enter into the midpoint of the carpaltunnel without proceeding at all into the median nerve. After theinjection site is identified, the site may be prepared with a topicalanesthetic spray or subcutaneous injection of a small dose of localanesthetic, prior to infusion of other medications.

In one preferred embodiment of the method of use of the instantinvention, after the needle is properly placed into the carpal tunnel ofthe afflicted extremity, a sterile, flexible plastic conduit or cannula50 (not shown) may be introduced into the interior of the flexibleneedle and then passed through to the terminus of the injection site.The needle tip may then be withdrawn while leaving the flexible cannula50 in place in the carpal tunnel. The cannula end opposite the injectionsite end may then be fitted with a needle-hub and connected to a syringeor other-delivery means for providing appropriate medication directly tothe carpal tunnel.

In a preferred embodiment of the method herein, syringe adapter 44 maybe connected to the conduit end opposite the injection site end offlexible cannula 50. Preferably this will be a multi-way valve, and morepreferably, a three-way valve connected at one port to cannula 50 and ateach of the remaining two ports to syringes 46 and 48, one of whichcontains a local, moderate to long duration injectable anesthetic andthe other of which contains a corticosteriodal preparation,respectively.

In this preferred embodiment, syringe 46 is a 5 cc. syringe containingroughly 3 to 5 cc. of a long-acting, local anesthetic agent. Suitableanesthetic agents include those which are non-irritating to the tissueto which they are applied and which do not cause any permanent damage tothe nerve structures, such as for example, Lidocaine, mepivacaine orbupivacaine. One preferred agent is a long duration Mepivacaine 5%solution. Syringe 48 is also a 5 cc. syringe containing a long-actingdepot form of a synthetic corticosteroid ester. Suitable corticosteroidsare those which possess high anti-inflammatory relative potencies suchas, for example, prednisolone, methyl-prednisolone, triamcinolone anddexamethasone, marketed under the trade names Hydeltrasol,Hydelta-T.B.A., Depo-Medrol, Medrol Acetate, Aristocort Diacetate andDecadron L.A. One preferred corticosteroid is methyl-prednisoloneadministered at a dosage range of approximately 1 to 2 milligrams perkilogram of body weight of the patient, preferably at 1.4 to 1.6milligrams per kilogram per injection.

Following insertion of the cannula and attachment of multi-way valvesyringe adapter 44 and syringes 46 and 48, the lever on the valve is setto permit introduction of the long-acting anesthetic from syringe 46into the injection site. After supplying sufficient local anestheticinto the carpal tunnel, the lever is then moved to permit introductionof the corticosteroid dosage from syringe 48 into the carpal tunnel.After supplying the corticosteroid, the cannula is withdrawn, the needleguide is removed and the forearm is removed from the armboard. Inconformity with sterile technique, it is also desirable to apply atopical antibiotic and bandage to the injection site. In some instances,it may also be desirable to apply a volar splint to immobilize the handand forearm for an eight to twelve hour period before resuming normalactivities with the afflicted extremity. The procedure may also berepeated on the opposite extremity where bi-lateral symptomatology ispresent.

FIG. 4 shows a cross-sectional schematic view of the apparatus shown inFIG. 3, taken along the lines 4a-4b. By placing the flexor-palmar creaseof the wrist portion of the forearm at wrist flexion curb 12, the wristis in approximately 20 degrees of dorsi-flexion. Side brackets 16 havebeen moved inwardly to bring forearm positioning surfaces 22 in contactwith the lateral surfaces of the forearm, preferably at the ulnar andradial styloids. Wrist bracket 24, carrying central needle guide 30 ispositioned over the forearm, thereby providing a visual cue as to thelocation of the carpal tunnel from between the two central tendons,indicated by the designations CT-1 and CT-2. Wrist bracket 24 rests onthe forearm on the palmar surface of the wrist and provides downwardforce on that surface to partially immobilize the wrist. After properplacement of centering pointer of wrist bracket 24, a flexible needle isadvanced into needle entrance 34, through needle channel 36 (shown inphantom detail) and out of needle exit 38. A flexible needle ofsufficient length to traverse the entire length of the needle guide andpermit the needle tip to enter into the carpal tunnel without proceedinginto the median nerve is used in needle guide 30. Syringe adapter 44 andsyringes 46 and 48 are shown at needle entrance 34. Cannula 50 havingcannula terminus end 52 is shown located in the carpal tunnel at a pointcephalad to the median nerve (MN).

In FIG. 5 there is shown a top plan view of the wrist bracket and needleguide portion of the apparatus of FIG. 1. Wrist bracket 24, includescentral needle guide 30 and a pair of wrist bracket adjustment slots 26for mounting the bracket to armboard 1 and for lateral adjustment of theneedle guide. Central needle guide 30 includes centering pointer 32,needle entrance 34, needle channel 36 (shown in phantom detail) andneedle exit 38. Centering pointer 32 includes viewing aperture 40 forvisual inspection of the injection site on the forearm anterior to thecarpal tunnel. As can be seen, needle exit 38 is located at or withinviewing aperture 40 and is situated at or near the proximal side end ofwrist bracket 24. Needle channel 36 is of sufficient length to allow anassociated flexible needle to traverse the entire length of the needleguide, exiting at needle exit 38, and to permit the needle tip to reachthe midpoint of the carpal tunnel. Channel needle 36 is also ofsufficient bore to accommodate from 20 to 26 gauge needles and ispreferably from 0.75 to 2.5 inches in length, from its starting point atneedle entrance 34 to needle exit 38. In one preferred embodiment,needle channel 36 is also curved downwardly, so that needle exit 38 isgenerally perpendicular to a proposed injection site. In other preferredembodiments, needle exit 38 may also be from approximately 20 to 80degrees off perpendicular, depending on, for example, the configurationof the wrist bracket itself, the angle of the slope or ledge of thewrist flexion curb and the location of the forearm and hand within thearmboard. In other preferred embodiments, the needle guide 30 may bemade removable from wrist bracket 24. After the forearm and wrist areproperly positioned by the wrist bracket, the needle guide may be placedin an opening adapted to receive the needle guide, within the wristbracket.

The foregoing descriptions are illustrative of the preferred embodimentsshown. The descriptions are not intended to limit the present inventionto the specific apparatuses and techniques shown and described, butinstead it will be appreciated that adaptations and modifications willbecome apparent from the present disclosure which are intended to bewithin the scope of the claims as set forth below.

What I claim is:
 1. An apparatus for supporting and securing a patient'sarm in palmar position during treatment of carpal tunnel syndromecomprising:a substantially rigid, rectangular, planar base adapted tosupport a human arm, said base having top and bottom surfaces, said topsurface defined by distal and proximal ends and two side ends, said topsurface proximal end further including an upper planar surface havingformed therein an arm support member and a distal end lower planarsurface, said upper and lower planar surfaces being separated by a wristflexion curb; a pair of substantially rigid forearm brackets detachablysecured to said top surface at or near said upper surface proximal endand positioned on opposite sides of said support member, said bracketsadapted to secure a first portion of said arm within said supportmember; a planar wrist bracket detachably secured to said upper planarsurface between said proximal and distal ends at or near said wristflexion curb and extending across said support member, said wristbracket adapted to compressively secure a second portion of said armwithin said support member; and a needle guide within said wristbracket, said needle guide comprising a centering printer, a viewingaperture and a needle conduit, said conduit comprising a needleentrance, a needle channel and a needle exit.
 2. The apparatus of claim1 wherein said arm support member is a "u-shaped" channel.
 3. Theapparatus of claim 1 wherein at least one of said forearm bracketsincludes lateral adjustment means.
 4. The apparatus of claim 1 whereinat least one of said forearm bracket pair is fixed in-place.
 5. Theapparatus of claim 1 wherein said forearm brackets further includeforearm positioning surfaces.
 6. The apparatus of claim 1 wherein saidwrist flexion curb is a slope of approximately 10 to 30 degrees.
 7. Theapparatus of claim 1 wherein said wrist bracket includes adjustmentmeans.
 8. The apparatus of claim 1 wherein said needle channel isdownwardly curved and said needle exit is perpendicular to said armsupport member.
 9. An apparatus for supporting and securing a patient'sarm in palmar position during treatment of carpal tunnel syndromecomprising:a substantially rigid, rectangular, planar base adapted tosupport a human arm, said base having top and bottom surfaces, said topsurface defined by distal and proximal ends and two side ends, said topsurface proximal end further including an upper planar surfacecomprising a first level surface defining a support member and a distalend lower planar surface comprising a second level surface, said firstand second level surfaces being separated by an inclined surface havingan incline of approximately 10 to 30 degrees; a pair of substantiallyrigid, moveable forearm brackets detachably secured to said top surfaceat or near said upper surface proximal end and positioned on oppositesides of said support member, said brackets adapted to secure a firstportion of said arm on said support member; a planar wrist bracketdetachably secured to said upper planar surface between said proximaland distal ends at or near said wrist flexion curb and extending acrosssaid support member, said wrist bracket adapted to compressively securea second portion of said arm on said support member; and a needle guideintegrally formed within said wrist bracket, said needle guidecomprising a centering pointer, a viewing aperture and a needle conduit,said conduit comprising a needle entrance, a needle channel and a needleexit.